James w



J. W.'IVORY.

RUBBER DAM PUNCH.

APPLICATION man JUNE 10. 1919.

Patented Nov. 11,

- JAMES we-Ivm or rmtaiiatrnia, PENNSYLVANIA;

RUBBER- DAM PUNCH,

Specification of Letters'Patent. Patented NOV. 11, 1919- Ap flication. fi ed June 10, .919. Serial No. 303,114. r

T 0 all whom it may concern.

Be it known that I, JAMEs W. IVORY, a subject of the King of Great Britain, res ding in the city and county of Philadelphia, State of Pennsylvania, have invented a new and -useful Rubber-Dam Punch, of which the following is a specification.

My invention consists in providing a rubber dam punch with a punching bit which.

is adapted to center itself true in the female member of the punch.

The invention is satisfactorily illustrated in the accompanying drawing, but the important instrumentalities thereof may be varied, and so it is to be understood that the invention is not limited to the specific details shown and described, as long as they are within the spirit or scope ofthe claims.

Figure 1 represents a side elevationv of a punch embodying my invention.

Fig. 2 represents a bottom plan view of a portion of the lower jaw of the punch;

Fig. 3 represents a longitudinal section of a portion of the upper jaw of the punch and the punching bit on an enlarged scale.

Fig. 4: represents a longitudinal section of a portion of. the lower jaw and appurtenances thereon, on an enlarged scale.

Fig. 5 represents a longitudinal section 0 a portion on line 55 Fig.3; a

Figs. 6, 7, 8 and Qrepresent longitudinal sections of other embodiments of my invention. I Fig. 10 represents a longitudinal section of a portion 011 line 1010 Fig. 7.

Figs. 11, 12 and 13 represent perspective views of diiferent forms of springs that may be employed in carrying out my invention.

Similar numerals of reference indicate corresponding parts in the figures.

Referring to the drawings.

1 designates a punch of a type having parallel acting jaws 2 and 3.

In the front of the jawis the chamber 4 which is occupied in part by the shank 5 of the punching bit 6, and in part by the springs or resilient members 7 said shank being surrounded by said springs and adapted to move vibratory in said chamber at. The ascent of the shank, and consequently of the bit is limited by a suitable shoulder shank 5 on the lower end of said shank, the same bearing freely against the underside of the 'aw 2.

1 The upper end of said shank extends above the top of the upper jaw 2 and is threaded for the connection therewith of the nut 8 which is adapted to be seated on said top of the aw 2 so as to retain the bit 6 in position, it being movable Vibratory on said top for which purpose the latter has therein a small recess 9 on which latter a portion of the underside of said nut is adapted to play.

7 1O designates the female member of. the punch,-.the same being of the form of a disk having therein a number ofspaced apart openings 11 of different diameter, said disk being adapted to be retained on the lower jaw 3 by the screw 12 which is passed through the center of the disk into the portion of the jaw 3 below the same, said disk being adaptedto be turned. so that either of the openings 11 may be placed below the point 13 of the punching bit so as to receive the latter in order to efliect the cutting action therein It will be noticed that the shank 5 of the 7 punching bit is subjected on its side in the chamber t to the pressure of the springs 7, and so sustained in proper posit-ion so that when the jaws 2 and 3 are closed the point of said bit may enter the respective opening in the d sk 6 below the same. Should, how-- ever, said point fail to'strike said opening 7 true as it contacts with the wall of said 7 opening, the bit will yield and vibrate owing tion 15, said tongues and portion surrounding the shank 5, while occupying the chamber 1, as has been stated, so that said central portion exerts its pressure on said shank, said portion yielding as the shank rolls, while the point of the bit enters the opening in the disk 6.

In Fig. 12 the spring is of the form of an elliptical or barrel shaped body 7 divided at intervals in its opposite ends so as to impart resiliency to said body.

In Fig. 6 the springs are of inverted V- shape, the apex of which is fitted in the underside of the nut 8, one of said springs being shown removed from the chamber in Fig. 13. a

I g- 8 the n t 8 is spherical and.

adapted to enter in part the chamber i, so as to roll or rock therein with the shank 5.

In Fig. 9 the shank 5 is reversely tapering on its opposite ends, while in the other figures, the shanks are cylindrical, but to the shape of the shank I do not limit myself.

Attention is particularly drawn to the fact that in all. cases the springs are con centric with the shank of the punching bit, and they surround the same, so as to produce equal pressure laterally on the side of said shank and while they retain said shank truly centrally in the chamber at and so preserve the right angular position of the bit and consequently its point to an opening in the female member of the punch they provide cushions which allow the shank to have a limited vibratory movement when the point of the bit does not fully register with said opening in its entrance thereinto, whereby said point will accommodate itself to any inequality in the line of descent of said point into said opening by its bearing in said opening and so be positioned as to enter said opening true and without resistance, and cause the punching of the rubber dam with openings that are out clean, perfect and without jaggedness.

After the punching of the rubber dam, the jaws are opened when the point of the bit recedes from the opening which it entered, when the springs cause the shank of the bit to be centered again true in the chamher, the effect of which on the bit is evident.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. In a punch of the character, stated, a

jaw having a piercing bit, said bit having a shank adapted to freely occupy a chamber in said jaw and vibrate therein, and cushioning resilient devices in said chamber adapted to press against the side of said shank and sustain the latter centered in said chamber and permit said shank and consequently said bit to yield aliningly in the event of inequality of alinement of the opening in the female member of the punch. 2. In a punch of the character stated, a jaw having a piercing bit, said bit having a shank laterally movable in a chamber in said jaw, and cushioning means in said chamber adapted to press against the side of said shank and center the latter true in said chamber preserving the bit true on its carrying-jaw, and permitting said shank and consequently said bit to vibrate to a limited extent means being provided for connecting said shank and consequently the bit with said jaw.

3. In a punch of the character stated, jaws having respectively a piercing bit and a female member the latter being provided with an opening therein adapted to receive the point of said bit, resilient means in the bit-carrying jaw, said bit having its shank sustained in a vibratory manner in said jaw by said resilient means adapting the bitto center itself in said opening in the event of an inequality of alinement of the opening in said member with said point of the bit.

JAMES w. IVORY.

Witnesses JOHN A. VVIEDERSHEIM, N. BUSSINGER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iatents,

' Washington, D. G. 

